The Y-stenting technique for bifurcation stenosis and bioprosthetic valve frame fracture prior to valve-in-valve transcatheter pulmonary valve replacement in a child

Introduction

Tetralogy of Fallot (TOF) corrective surgery, especially using a transannular patch, carries a high risk of reintervention [1]. Surgical pulmonary valve replacement with a bioprosthetic valve (BPV) is a well-established method of treating postoperative right outflow tract dysfunction [2]. Since BPV function deteriorates and patient-prosthesis mismatch increases with growth, reintervention is necessary. To avoid the reoperation risk, valve-in-valve (ViV) transcatheter pulmonary valve replacement (TPVR) has become an attractive alternative [3]. The BPV true inner diameter (ID) is shorter than the nominal BPV size by 2 mm or more, which limits the ViV therapy [4]. The valve implanted within the BPV makes the effective lumen even narrower. Since the first report by Tanase et al. [5], intentional fracture of the BPV frame using ultra-high-pressure balloons has become a valuable option to optimize the hemodynamic outcomes of ViV in the BPV in a pulmonic position [6].

Case report

The case concerns a 17-year-old, 69 kg, asymptomatic boy after a TOF complete repair with a transannular patch. The patient was re-operated at the age of 10 with a stentless valve and only 1 year later with a 23 mm Carpentier-Edwards Perimount Magna bioprosthetic valve (Edwards Lifesciences Inc., Irvine, USA). Pulmonary stenosis (PS) with maximum/mean gradient of 100/55 mm Hg, moderate pulmonary regurgitation, and dilated right ventricle were established during transthoracic echocardiography. Computed tomography (CT) revealed a 12 mm supravalvular PS and proximal narrowing of pulmonary arteries: right (RPA) to 9 and left (LPA) to 6 mm (Figure 1 A).
In order to test transcatheter treatment options, a 3D CT-derived silicone model of the aforementioned region with an embedded valve was prepared. Subsequently, the Y-stenting technique for bifurcation stenosis was selected. This includes implantation of a long hybrid-cell designed stent into the supravalvular PS and LPA and another stent into the RPA through the struts of the first stent (Figure 1 B). Moreover, an experimental bench test with cracking of the 23 mm Magna BPV using a 24 mm Atlas balloon (Bard Peripheral Vascular Inc., Tempe, USA) was performed. The lower restrictive frame of the valve cracked at 14 atm. A preprocedural CT scan excluded risk of coronary artery compression in the intended valve landing zone. Finally, the patient was qualified for ViV TPVR and informed consent was...


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